Expanding on what Dan said, there really are no drones in the $400 range that have good avoidance. The Mavic Air 1 has some of that technology so if you can find a used one it would fit the bill but avoidance in even the newer, drones is still prone to failures so I wouldn't rely on it. The most important sensors are on the bottom of the drone and keep it from crashing to the ground plus guide the craft to a good landing.
Thank you for all the suggestions. The reason I am looking for one is my friend is just learning to fly a drone and I know he, like myself, and I’m sure many of you crashed a few times before you got the hang of it.